Territorial song and song neighbourhoods in the Scarlet Rosefinch Carpodacus erythrinus

Abstract

Throughout the range of the Scarlet Rosefinch, its territorial song consists of 3–9 (usually 4–5) elements, of which there are 5 different types. The differences lie in the way the pitch of the element changes in time (frequency “slope”) and the width of the frequency band. Within a given type of song, the various elements can be present in almost any combination. Therefore, so many song types can be formed that the songs in even small parts of the species’ area are clearly distinct from one another. Despite this capacity for variation, however, by chance identical songs may be sung in widely separated parts of the area, in some cases by different subspecies. The species has not developed large‐scale dialects or regiolects based on a song tradition acquired during an early imprinting phase. Scarlet Rosefinches tend to breed in small colonies, groups of up to about 15 pairs characterized by the same type of song (song neighbourhoods, formed by the development of a microlect). Microlects develop by a founder effect. When males, near one‐year old or older, join one another to form isolated colonies after arrival in the breeding region, they adopt (“learn”) the song type that will eventually characterize the colony from the first male to arrive at the site. After the colony has been founded, in most cases each male uses only one type of song during a breeding season, with practically no variation of the temporal and frequency parameters. Singing the same type of song, the members of a colony accept one another sufficiently to allow the breeding territories to be closely packed. It appears that a long‐lasting capacity for acoustic learning, in combination with colony‐like breeding and great ecological flexibility, has allowed the Scarlet Rosefinch to become the most successful species of the genus Carpodacus.

Correlated evolution between repertoire size and song plasticity predicts that sexual selection on song promotes open-ended learning

“…~day 25–90 in zebra finches), after which no new song elements are acquired (Böhner, 1990; Immelman, 1969; Nottebohm, 1984). Other species appear to delay song crystallization until some time in adulthood (Dowsett-Lemaire, 1979; Kipper and Kiefer, 2010; Martens and Kessler, 2000); for example, chipping sparrows appear to have a second sensitive period immediately after their first migration, following which their song crystallizes (Liu and Kroodsma, 2006; Liu and Nottebohm, 2007). Still other species can continue to acquire new syllables or songs throughout their lives (Adret-Hausberger et al, 2010; Espmark and Lampe, 1993; Gil et al, 2001; Hausberger et al, 1991; Mountjoy and Lemon, 1995; Price and Yuan, 2011).…”

Phylogenetic Signal in the Song of Crests and Kinglets (Aves: Regulus)

“…Song tradition has been proven to work accurately, either in experiments with captive birds or in long-term field studies. They reveal the persistence of certain song types over time beyond the life span of an individual male (Nicolai 1959;Thielcke 1984;Payne 1986;Payne and Payne 1996;Martens and Kessler 2000). But copying errors during the sensitive phase of song learning can produce new individual vocal repertoires (Thielcke 1970) and may lead to the establishment of dialects.…”

Are simple plumage traits sufficient for species discrimination by harrier males?

“…The response behaviour is then dependent on perceived similarity between the target and the own phenotype (see an overview in Tang‐Martínez 2001). In harriers, like in other birds, individuals may learn conspecific traits as early as nestlings by association with their parents (Jouventin et al 1999), or later on by experience with other conspecifics (Martens and Kessler 2000). According to my results, simple plumage traits like colour and plumage patterns would be incorporated to the learned ‘template’ to be compared with newly encountered individuals (Tang‐Martínez 2001).…”